Early readers — illustrated books for children who are starting to read on their own — often fail for the same reason that many picture books do: An author-illustrator draws better than he or she writes or vice versa. Or, if the words and pictures come from different people, the writer and artist are mismatched.

The late Paula Danziger’s popular books about the elementary-school student Amber Brown owe much of their success to Tony Ross’s entertaining pictures. Ross’s line drawings resemble those of his countryman Quentin Blake in their ability to evoke many moods in a believable way. And the sure-footedness of his pictures may help to explain why Danziger was able to spin off the “A Is for Amber” early-readers series from her orginal chapter books about Amber Brown.

The chapter books follow the upbeat, pun-loving Amber as she deals with events such as her best friend’s move to another state and the divorce and new loves of her parents. And the early readers are, in effect, an extended prequel to them. Along with the chapter books, these easier books offer a welcome alternative to Barbara Park’s novels about Junie B. Jones, who at times acts like a charter member of the Future Sociopaths of America. Amber has high spirits that she expresses without the unrepentant nastiness that characterizes much of Junie’s behavior.

But I was at first confused by the early reader Orange You Glad It’s Halloween, Amber Brown?, which I picked up after having enjoyed several of the chapter books. Why does Amber notice, as she prepares Pumpkin Day at school, that her mother and father haven’t been getting along? Have her divorced parents gotten back together? Why is Justin, her best friend who has supposedly moved away, decorating pumpkins with her? And why does Ross’s art look different?

With help from the Internet, I sorted it out: I was reading an installment in the six-book prequel about events that occurred before the divorce and Justin’s move, a newer series with simplified color art by Ross instead of the black-and-white drawings of the original. No doubt all of this will be less confusing to children, who will read the early readers first, than it was to me. And Orange You Glad Its Halloween, Amber Brown? has many of the virtues of the chapter books, particularly Amber’s engaging first-person narration. But the added backstory — as in so many prequels — is just padding.

Grandmas Trick-or-Treat comes from an author-illustrator who won the Caldecott Medal for Mirette on the High Wire, and it may appeal anyone who has wondered: Why do so many children’s books still show grandmothers stereotypically baking cookies? This is the fourth book about a girl named Pip and her two grandmothers, Nan and Sal, whose clashing personalities drive much of the humor in the series. Proper Grandma Nan goes trick-or-treating with Pip in her street clothes — a miniskirt, striped tights, and dangling earrings. Playful Grandma Sal wears a mummy’s costume. But the two women team up to outfox a bully who taunts Pip on Halloween, showing that people with different temperaments can work together.

Neither of these books evokes as much emotion as such superior early readers as Cynthia Rylant’s “Henry and Mudge Ready-to-Read” books oneminutebookreviews.wordpress.com/2007/12/07/. But both come from authors who know how to hold the attention of 4-to-8-year-olds. Intended for children who are starting to read on their own, these books would also work as read-aloud stories for some younger ones.

Best line/picture: Ross’s picture of Amber Brown pretending to be a werewolf with candy corn fangs.

Worst line/picture: Amber’s observation, “It will be a sad Halloween if my parents are not getting along.” A child might have a sad holiday because her parents were fighting, but this comment has little context in the story. Its only emotional authenticity comes from what we know from other books in the series.